Concentration of sylvinite ores



Patented May 23,. 1944 Arthur J. Weinig, Golden, C010,, assignor to Potash Company of America, Denver, 0010., a

corporation of Colorado No Drawing. Application February 3, 1940,

Serial No. 317,315

4 Claims.

ess for the separation of the'soluble constituent of sylvinite ores. Sylvinite ore consists of sodium chloride and potassium .chloride crystals as principal constituents, together with minor inclusions of other mineral matter, such as iron and manganese oxides, polyhalite, clays and the like generallyclassed as gangues.

The invention relates primarily to the-separation of certain salts of the ore to the end that potassium chloride may be recovered as a substantially pure product, and it is an object of the invention to provide a simple, inexpensive and emcient treatment by which the potassiumchloride constituents are-selectively floated in a. froth for separation from other constituents of the ore.

Another object of the present invention is to provide a class of reagents eflective for promoting frothing and collection of potassium chloride constituents of sylvinite ore in a froth flotation operation.

. (Cl. 209-166) 1 This invention relates to a froth flotation procwell'as certain specific members other than those claimed in the aforesaid application.

The class of reagents found effective for purposes of the present invention may be designated as alkali salts of a sulfated aliphatic alcohol having from five to fourteen carbon atoms in the molecule, namely, sulfates of amyl alcohol and of each successive member of the homologous series satisfactory results, and eventhos'e members im- I frothing, collection, promotion and selection in the froth flotation of ores of the above described In such a flotation treatment, the pulp-forming step involves the introduction of the ore in flnelydivided condition into a solution saturated with,

respect to both sodium chloride and potassium chloride and. which usually is'a saturated solution of the ore. Dissolution of the soluble particles of ore is prevented in this way. A corresponding I for Concentration process, and Serial No. 38,316,

filed August 28, 1935, for Flotation process for sylvinite ores, which were patented February 6, 1940, and numbered respectively No. 2,188,931 and No. 2,188,932.

Features describedbut not claimed in the aforesaid applications are being claimed herein. Thus,

application Serial No. 38,316 discloses a'milling operation inclusive of a flotation circuit utilinng separation methods of the present case, but the claims of said' application are restricted to procedural details of the milling circuit and do not claim the flotation separation P r se.

Similarly, application Serial No. 7,219 discloses substantially the same class of reagents described and claimed herein. However, the claims of said application are specific to designated members of character in a pulp of the type described.

The ore is prepared for treatment in the usual way by grinding or otherwise reducing-the same to a'finely-divided condition. While each operation involves some variations in treatment based upon variable characteristics of the ore and similar conditions, grinding to minus forty-eight mesh may be taken as a standardfor efllcient operation.

The ground ore is entered into th aforemention'ed saturated solution and it will be understood that anyof the well-known methods of dry or wet grinding may be employed. However, in practice it has been found desirable to employ wet grinding in a pebble mill in closed circuit with a classifier using the saturated solution as the liquidphase of this operation.

The pulp is then conducted to any suitable froth flotation apparatus and subjected to selective fl tationby the use of a-reagent, which may be y one of the aforementioned compositions, or mixtures thereof. The reagent may be mixed initially with the pulp before being subjected to agitation and aeration, or, l.f more convenient, both pulp and reagent may be introduced into the flotation tank separately and mixed by the agitative action of the process.

In the flotation apparatus, the agitation and aeration serve to bring the reagent in intimate contact with the solid constituents, and as the reagent has a strong afilnity for potassium chloride or constituents containing it, these solids adhere "to rising gas bubbles and carry to the surface in a froth and subsequently are removed in a manner well-known in the art.

class, while the present application will be filled upon to cover the clas in generic terms. as 56 constituents in the aforementioned saturated so- The reagent has no afllnity for sodium chloride lution, and as a result, these solids remain in an unfloated condition, which at the completion of the separation are removed from the apparatus as a waste or tailings product.

While I do not wish to be limited to any exact proportions in the use of the compositions comprising the reagent, satisfactory results have been obtained by the use of from one-fourth to twenty pounds of reagent per ton of ore, and preferably the amount used should be approximately four pounds per ton of ore.

To afford a better understanding of the operating procedure, reference will be made to several test operations. In the first of these, sylvinite ore from the Carlsbad, New Mexico, field was subjected to treatment. This ore in finely-divided condition was introduced into a saturated solution of the ore to which was added a solution of sodium lauryl sulfate (12 carbon atoms in the molecule) and subjected 'to a froth flotation treatment. The froth overflow product of the resulting separation was found to contain an average of seventy-three per cent potassium chloride content in an amount equal to forty-seven per cent of the weight of ore taken. The ore taken for test contained forty-two per cent potassium chloride, and consequently a recovery of eighty-one per cent was obtained.

In another test, five hundred grams of minus sixty-five mesh sylvinite ore from the Carlsbad, New Mexico, field was takenfor test. This material was introduced into a saturated solution of the ore and subjected to a froth flotation treatment in the presence of two cc. of five per cent sodium octyl sulfate solution (eight carbon atoms in the molecule). In this testing, the following results were obtained:

The foregoing testing demonstrates that the members of the homologous seriesintermediate five hundred grams of thirty-five mesh sylvinite ore was introduced into a saturated solution of the ore and mixed with twenty cc. of a concentrated solution of sodium amyl sulfate. This pulp was subjected to a froth flotation treatment and a relatively feeble flotation of KCl was obtained. From the foregoing, it will be evident that the respective members of the homologous series will be effective in promoting the separation of KCl from other constituents of sylvinite ores and the tests cited herein serve as a guide in the selection of the-respective members for both commercia and scientific purposes.

Inasmuch as each ore treated, and sometimes ore from different portions of the same deposit,.

will vary in physical and chemical properties to a degree sufllcient to require variations in flotation procedure, preliminary testing of the individual members of the group will disclose which reagentshould be used to obtain the most eflicient separation in the treatment of any given ore.

However, the general characteristics described herein will provide a basis for asimplified selection of the proper reagent.

Changes and modifications may be availed of within the spirit and scope of the invention as defined in the hereunto appended claims.

What I claim and desire to secure by Letters Patent is: 4

l. The process of treating sylvinite ore, which comprises the treatment of such an ore in a solution saturated with respect to sodium chloride and potassium chloride and containing sodium chloride particles and potassium chloride parti-' cles in undissolved form, preferentially filming the undissolved potassium chloride particles with a collector reagent consisting of an alkali salt of a sulfated al'cohol having from five to fourteen carbon atoms in the molecule, and froth floating the particles so filmed on thesurface of the solution.

2. The process of treating sylvinite ore, which comprises the treatment of such an ore in a solution saturated with respect to sodium chloride and potassium chloride and containing sodium chloride particles and potassium chloride partlcles in undissolved form, preferentially filming the upper and lower limits specified are effective J'- for promoting a separation sufiiciently eflicient for commercial purposes. Those members at the .upper and lower limits give a rather weak action and are important principally in measuring the limits of the range.

In this connection, such reagents are relatively twenty pounds of reagent per ton of ore treated.

expensive, particularly the sulfated myristic alcohol (fourteen carbon atoms), for which reason" preference would usually be given to the more efllcient members of the series providing a reduction in operating costs.

To provide a comparison, a test is cited in which.

the undissolved potassium chloride particles with,

a collector reagent consisting of an alkali'salt of a sulfated aliphatic alcohol having from five to fourteen carbon atoms-in the molecule, and froth floating the particles so filmed on the surface of the solution.

3. A process according to claim 2 in which the collector reagent is present in the treatment in the approximate proportion of one-fourth to 4. A process according to claim 2 in which the jreagent is present in the treatment in the ap- 

